WO2010030101A2

WO2010030101A2 - Electrostatic chuck comprising a double buffer layer (dbl) to reduce thermal stress

Info

Publication number: WO2010030101A2
Application number: PCT/KR2009/005068
Authority: WO
Inventors: 최진식; 최정덕
Original assignee: 주식회사 코미코
Priority date: 2008-09-09
Filing date: 2009-09-08
Publication date: 2010-03-18
Also published as: KR100984751B1; KR20100030169A; CN102150252B; TW201021153A; TWI379380B; CN102150252A; WO2010030101A3

Abstract

Disclosed is an electrostatic chuck (ESC) comprising a buffer layer to absorb thermal stress. The electrostatic chuck comprises: a main body having transverse holes; a base plate disposed on the upper side of said main body and including insertion holes corresponding to said transverse holes, and an electrode layer partially exposed through said insertion holes, to secure an object to be held by the electrostatic energy of said electrode layer; a terminal unit having a contact terminal connected to said electrode layer through said transverse holes and insertion holes, and insulating members for electrically insulating said contact terminal and said main body; a first buffer layer disposed at at least part of the boundary between said main body and said insulating member to block the transfer of thermal stress from said main body to said insulating members; and a second buffer layer disposed at at least part of the boundary between said main body and said base plate to block the transfer of thermal stress from said main body to said insulating members. According to the present invention, the buffer layers of the electrostatic chuck absorb thermal stress, thereby minimising cracks due to thermal stress and extending the life of the chuck.

Description

Electrostatic chuck with double buffer layer for thermal stress reduction

The present invention relates to an electrostatic chuck including a double buffer layer that suppresses the generation and propagation of cracks due to thermal stress. More specifically, thermal stress is absorbed by the first buffer layer formed at the point where thermal stress occurs in the electrostatic chuck, and generation of cracks is suppressed, and propagation of cracks generated by the second buffer layer is suppressed, The present invention relates to an electrostatic chuck in which crack generation and propagation due to thermal stress generation are minimized and thus life is extended.

In the manufacturing process of a flat panel display such as a semiconductor or LCD, a deposition process such as chemical vapor deposition (CVD) or an etching process such as reactive ion etching (RIE) is performed. At this time, in order to secure the reliability of the process, it is necessary to fix the substrate (silicon wafer, glass substrate, etc.) to a predetermined position in the deposition chamber or the etching chamber, for example, the electrode. For this purpose, an electrostatic chuck (ESC) is included in the deposition chamber or the etching chamber to fix the substrate in place.

1 is a cross-sectional view showing the configuration of a conventional electrostatic chuck.

As shown in FIG. 1, the conventional electrostatic chuck 100 is embedded in an aluminum body 101 as a base substrate, a ceramic substrate 102 for fixing a substrate seated on an upper surface, and a ceramic substrate 102 to be electrostatically charged. The electrode 103 includes a terminal 103 for generating a high voltage, a terminal 104 for applying a high voltage to the electrode 103, and an insulating member 105 surrounding the outside of the terminal 104.

The electrostatic chuck 100 is operated by the electrode 103 generating an electrostatic force when a high voltage from an external power source is transmitted to the electrode 103 through the terminal 104. That is, the electrostatic force is transmitted to the upper surface of the ceramic substrate 102, the substrate can be fixed and maintained.

On the other hand, due to the plasma generated during the deposition process or the etching process, the ceramic substrate 102 receives heat to generate a thermal stress (thermal stress due to plasma temperature) to shorten the life of the electrostatic chuck. Specifically, heat generated in the ceramic substrate 102 by the plasma is transferred to the aluminum body 101, thereby causing the aluminum body 101 to thermally expand. At this time, the thermal stress is generated by the difference in the coefficient of thermal expansion between the aluminum body 101, the ceramic substrate 102, and the insulating member 105, the thermal stress is the portion A of FIG. Maximum at the end of the interface between the insulating members 105.

This thermal stress is propagated toward the relatively weak strength ceramic substrate 102, which causes cracks in the ceramic substrate 102, which is secondaryly grown and propagated to the upper portion of the ceramic substrate 102. For this reason, when the operation of the electrostatic chuck 100 is repeated, the degree of cracking of the ceramic substrate 102 becomes more severe, and there is a problem in that the life is shortened.

Therefore, there is a need to develop a technology that can extend the life of the electrostatic chuck by minimizing the occurrence of cracks of the internal components of the electrostatic chuck.

One embodiment of the present invention for improving the problems related to the life shortening of the electrostatic chuck as described above provides an electrostatic chuck having first and second buffer layers capable of absorbing the thermal stress of the body portion of the electrostatic chuck.

Another embodiment of the present invention provides a method of manufacturing the electrostatic chuck.

In order to achieve the above object, the electrostatic chuck according to an object of the present invention is partially through a body portion having a through hole, an insertion hole corresponding to the through hole and corresponding to the through hole and partially through the insertion hole. Including an electrode exposed to the base portion for fixing the object by the electrostatic force of the electrode, the connecting terminal connected to the electrode through the through hole and the insertion hole and the insulating member to electrically insulate the connecting terminal and the body portion A first buffer layer disposed on at least a portion of the interface between the terminal portion and the body portion and the insulating member to block the thermal stress from being transferred to the insulating member, and on at least a portion of the boundary portion between the body portion and the base portion. And a second buffer layer which blocks thermal stress from being transferred to the insulating member. Include.

In example embodiments, the first buffer layer may be further disposed on an interface between the base portion and the insulating member, and the first buffer layer and the second buffer layer include a ceramic material. The thicknesses of the first buffer layer and the second buffer layer may have a range of 100 μm to 250 μm. In addition, the surface roughness of the first buffer layer may be in the range of 0.1 μm to 2 μm, and the surface roughness of the second buffer layer may have a range of 3 μm to 7 μm.

In one embodiment, the porosity of the first buffer layer and the second buffer layer is equal to or greater than the porosity of the ceramic base portion, for example, may have a porosity of about 2 to 10%.

According to a method of manufacturing an electrostatic chuck for achieving another object of the present invention, there is provided a body portion having a through hole, and having a first buffer layer corresponding to the through hole and absorbing the thermal stress of the body portion on an outer surface thereof. Prepare the terminal part. The terminal part is inserted into the through hole so as to be exposed to an upper surface of the body part, and a second buffer layer is formed on an upper surface of at least a portion of the body part and an upper surface of at least a portion of the first buffer layer. A lower base layer is formed on the buffer layer to expose the top surface of the terminal portion, and an electrode layer is formed on the lower base layer in contact with the top surface of the terminal portion. An upper base layer is formed on the lower base layer and the electrode layer to complete the electrostatic chuck.

In some embodiments, the first and second buffer layers may be coated in an atmospheric plasma spraying process.

According to one embodiment of the present invention, the thermal stress is absorbed by the buffer layer included in the electrostatic chuck, thereby minimizing the occurrence of cracks due to thermal stress, thereby extending the life of the electrostatic chuck.

In addition, according to the present invention, thermal stress is absorbed by the first buffer layer included in the electrostatic chuck to suppress the generation of cracks due to thermal stress, and even if cracks are generated, the propagation of the electrostatic chuck is suppressed by the second buffer layer. The life can be extended even further.

2 is a cross-sectional view showing the configuration of an electrostatic chuck according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the electrostatic chuck and the terminal portion for the electrostatic chuck and its manufacturing method according to an embodiment of the present invention.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

As shown in FIG. 2, the electrostatic chuck 200 is formed on the body portion 201 and the body portion 201 as a base substrate and is embedded therein while fixing and maintaining a processing object (not shown) such as a substrate. A base plate 202 having an electrode layer 203 for generating an electrostatic force, a terminal 204 for transmitting a high voltage applied from an external power source to the electrode layer 203, and an insulating member 205 surrounding the outside of the terminal 204. A first buffer layer 206a and a base portion 202 disposed on at least a portion of the terminal portion including the terminal portion and the interface between the body portion 201 and the insulating member 205 and the boundary portion between the base portion 202 and the insulating member 205. ) And a second buffer layer 206b formed in a region including an interface between the insulating member 205 and the insulating member 205.

The body portion 201 is made of a conductive material such as aluminum, and functions as a base substrate of the electrostatic chuck 200. The through hole 207 may be formed in the center of the body portion 201 so that the terminal 204 constituting the electrode portion and the insulating member 205 can be inserted therethrough.

The base portion 202 is a dielectric having a predetermined dielectric constant, and may be formed on the body portion 201 by an Atmospherically Plasma Spray (APS) coating method. Base 202 may comprise a ceramic. Examples of the ceramics include Al ₂ O ₃ , Y ₂ O ₃ , Al ₂ O ₃ / Y ₂ O ₃ , ZrO ₂ , AlC, TiN, AlN, TiC, MgO, CaO, CeO ₂ , TiO ₂ , B _x C _y , BN, SiO ₂ , SiC, YAG, Mullite, AlF ₃ and the like. At this time, these ceramics can be used individually or in combination.

The base 202 serves to fix and hold the substrate by using electrostatic force. To this end, an electrode layer 203 for generating electrostatic force may be buried in the base 202. The top surface of the base portion 202 is preferably horizontal to allow the substrate to be seated. The electrode layer 203 may be formed to be substantially parallel to the top surface of the base portion 202.

An insertion groove 208 may be formed in the center portion of the base portion 202 so that the terminal 204 may be inserted to be connected to the electrode layer 203. The terminal 204 may be inserted from the outside and connected to the electrode layer 203 through the through hole 208 formed in the body portion 201 and the insertion groove 208 formed in the base portion 202.

As described above, the electrode layer 203 is embedded in the base 202, and receives a high voltage from the terminal 204 to generate an electrostatic force on the top surface of the base 202. The substrate may be seated on the upper surface of the base 202 by the generated electrostatic force and may be fixed and maintained.

The electrode layer 203 is preferably made of a conductive material such as nickel.

The method of embedding the electrode layer 203 in the base portion 202 may be performed by first forming the lower base layer 202a by using the atmospheric plasma spray coating method, and then forming the electrode layer 203 by using the atmospheric plasma spray coating method thereon. It is preferable to form the upper base layer 202b on the secondary by using the atmospheric plasma spray coating method. At this time, the electrode layer 23 may be formed using screen printing as needed.

The thickness of the lower base layer 202a is preferably 400 μm to 600 μm, the thickness of the electrode layer 203 is 5 μm to 65 μm, and the thickness of the upper base layer 202 b is adjusted within the range of 400 μm to 750 μm.

The terminal 204 is connected to the electrode layer 203 through the through hole 208 and the insertion groove 209 and transmits a high voltage from the external power source (not shown) to the electrode layer 203. The terminal 204 is preferably made of a conductive material such as tungsten, molybdenum, titanium, or the like.

Meanwhile, an insulating member 205 is formed between the body portion 201 and the terminal 201. The insulating member 205 insulates the body portion 201 and the terminal 204. The insulating member 205 is preferably made of a ceramic sintered body. Ceramic sintered body has the advantage that can maximize the insulation because there are few pores.

At this time, it is preferable that the thickness of the insulating member 205 is set to approximately 2,000 m. In addition, the surface roughness of the insulating member 205 is preferably adjusted within the range of 0.1 to 2㎛ in order to reduce the occurrence of arcing by lowering the surface resistance, it is more preferably adjusted to the range of 1㎛ or less.

In the present invention, the first buffer layer 206a may be formed in the electrostatic chuck 200 at the boundary between the body portion 201 and the insulating member 205 and at the boundary between the base portion 202 and the insulating member 205. It is a characteristic configuration. The first buffer layer 206a may include a ceramic. Examples of the ceramics include Al ₂ O ₃ , Y ₂ O ₃ , Al ₂ O ₃ / Y ₂ O ₃ , ZrO ₂ , AlC, TiN, AlN, TiC, MgO, CaO, CeO ₂ , TiO ₂ , B _x C _y , BN, SiO ₂ , SiC, YAG, Mullite, AlF ₃ and the like. At this time, these ceramics can be used individually or in combination. The first buffer layer 206a may be formed using an Atmospherically Plasma Spray (APS) coating method.

The thickness of the first buffer layer 206a is preferably adjusted within the range of 100 μm to 250 μm, but more preferably within the range of 150 μm to 200 μm. If the thickness of the first buffer layer 206a is thicker than the thickness range, pores may be generated inside the first buffer layer 206a, and cracks may occur. If the thickness of the first buffer layer 206a is thinner than the thickness range, the first buffer layer 206a may be formed. There is a risk of not playing a role.

In addition, the surface roughness of the first buffer layer 206a is preferably adjusted within the range of 0.1 μm to 2 μm to reduce the occurrence of arcing by lowering the surface resistance, but more preferably adjusted to the range of 1 μm or less.

The first buffer layer 206a absorbs the thermal stress generated by the temperature rise of the electrostatic chuck 200 due to the plasma generated inside the chamber during the deposition process or the etching process. As described above, conventionally, thermal stress is generated by the expansion of the aluminum body 101 by the conduction of heat due to the temperature rise of the electrostatic chuck 100 due to the plasma temperature. However, in the present invention, the thermal stress generated when the electrostatic chuck 200 receives the heat to expand the body 201 is absorbed by the first buffer layer 206a without being directly transmitted to the insulating member 205. do. As described above, in the present invention, since the first buffer layer 206a absorbs the thermal stress at the point where the thermal stress is maximum (refer to part A of FIG. 1), the body portion 201 and the insulating member ( The occurrence of cracks at the end of the interface between the 205 can be suppressed, as a result of which the life of the electrostatic chuck 200 can be extended.

In the present invention, the second buffer layer 206b is formed in the region including the interface between the base portion 202 and the insulating member 205 in the electrostatic chuck 200. The region where the second buffer layer 206b is formed may include a portion of an interface between the base portion 202 and the insulating member 205 and an interface between the body portion 201 and the base portion 202. The upper surface of the second buffer layer 206b may be formed to be spaced apart from the electrode layer 203 embedded in the base 202 by a predetermined distance. The second buffer layer 206b may include a ceramic. Examples of the ceramics include Al ₂ O ₃ , Y ₂ O ₃ , Al ₂ O ₃ / Y ₂ O ₃ , ZrO ₂ , AlC, TiN, AlN, TiC, MgO, CaO, CeO ₂ , TiO ₂ , B _x C _y , BN, SiO ₂ , SiC, YAG, Mullite, AlF ₃ and the like. At this time, these ceramics can be used individually or in combination. The second buffer layer 206b is preferably formed using an APS Atmospherically Plasma Spray coating method.

The thickness of the second buffer layer 206b is preferably controlled within the range of 100 μm to 250 μm, but more preferably within the range of 150 μm to 200 μm. If the thickness of the second buffer layer 206b is thicker than the thickness range, pores may be generated in the second buffer layer 206b to cause cracks, and if the thickness of the second buffer layer 206b is thinner than the thickness range of the second buffer layer 206b, There is a risk of not playing a role.

In addition, the surface roughness of the second buffer layer 206b is preferably adjusted within the range of 3 μm to 7 μm in order to reduce the occurrence of arcing by lowering the surface resistance, but more preferably adjusted within the range of 4 μm to 6 μm. . If the surface roughness of the second buffer layer 206b exceeds the surface roughness range, the strength of the second buffer layer 206b may drop, and the second buffer layer 206b itself may fall off, and the surface roughness may not reach the surface roughness range. In this case, the surface of the second buffer layer 206b is so smooth that there is a possibility that the lower base layer 202a formed on the second buffer layer 206b may not adhere well in the future.

The second buffer layer 206b plays a role of suppressing propagation of cracks generated even though the first buffer layer 206a is formed. That is, when the first buffer layer 206a does not completely absorb thermal stress, cracks may occur at the end of the interface between the body portion 201 and the insulating member 205, which is relatively brittle. It may propagate toward the base 202 and eventually damage the base 202, where the second buffer layer 206b located above the first buffer layer 206a suppresses the propagation of cracks toward the base 202. As a result, the lifespan of the electrostatic chuck 200 can be extended.

As described above, in the present invention, the thermal stress generated by forming the first buffer layer 206a and the second buffer layer 206b around the contact portion of the body portion 201 and the insulating member 205, which is the point where the thermal stress is maximized. By absorbing in two steps, it is possible to prevent the shortening of the life of the electrostatic chuck 200 due to crack generation.

Meanwhile, in the present invention, the first buffer layer 206a and the second buffer layer 206b absorb the thermal stress as described above so as to effectively perform the role of suppressing crack generation and propagation. The porosity of the ceramic constituting the 206a and the second buffer layer 206b is equal to or higher than the porosity of the base portion 202, that is, the lower base layer 202a or the upper base layer 202b. For example, the porosity of the ceramic constituting the first buffer layer 206a and the second buffer layer 206b is preferably controlled in the range of 2% to 10%, more preferably in the range of 2% to 7%. When the porosity of the first buffer layer 206a and the second buffer layer 206b exceeds the porosity range, pores increase in the first buffer layer 206a and the second buffer layer 206b, and thus the first buffer layer 206a and If the strength of the second buffer layer 206b is lowered and even the first buffer layer 206a and the second buffer layer 206b itself fall off, and fall within the porosity range, the first buffer layer 206a and the second buffer layer 206b may fall. There is a risk of cracking in the buffer layer 206b.

Further, in the present invention, it is preferable that the edge portions of the first buffer layer 206a and the second buffer layer 206b have a round shape that is not sharp or a chamfered shape. This is because when the edge portions of the first buffer layer 206a and the second buffer layer 206b have sharp shapes, stress may be concentrated at the sharp portions, thereby increasing the probability of cracking.

Meanwhile, referring to FIG. 2, due to the inclined surface of the body portion 201, the density of the lower base layer 202a of the A region on the inclined surface of the body portion 201 is lower than that of the B region on the body portion 201 excluding the inclined surface. It may be relatively lower than the density of the base layer 202a. However, since the thickness of the region A is greater than the thickness of the region B, current leakage through the pores included in the lower base layer 202a of the region A may be reduced. Therefore, the occurrence of arcing between the body portion 201 and the electrode layer 203 can be reduced.

In addition, since the lower base layer 202a of the region A is relatively thick even if the density of the lower base layer 202a of the region A is relatively low, the lower base layer of the interface portion between the body portion 201 and the insulating member 205. Crack generation in 202a can be prevented. Therefore, the occurrence of arcing between the body 201 and the electrode layer 203 through the crack can be reduced.

In addition, an adhesive layer (not shown) may be further provided between the body portion 201 and the lower base layer 202a. The adhesive layer bonds the body portion 201 and the lower base layer 202a. The adhesive layer has a thermal expansion rate between the thermal expansion rate of the body portion 201 and the thermal expansion rate of the lower base layer 202a, and buffers between the body portion 201 and the lower base layer 202a having different thermal expansion rates. The adhesive layer may include a metal alloy. Examples of the metal alloys include nickel-aluminum alloys.

2, when the lower base layer 202a covers the body 201, the terminal 204, and the insulating member 205, the upper surface of the lower base layer 202a is higher than the upper surface of the terminal 204. It is desirable to. This causes the thickness of the upper base layer 202b in the C region located above the terminal 204 to be thicker than the thickness of the upper base layer 202b in the remaining D region, so that a high voltage power supply is applied to the electrode layer 203 through the terminal 204. This is to prevent the discharge phenomenon between the electrode layer 203 and the substrate which is supported on the upper base layer 202b even if it is applied to.

Hereinafter, a method of manufacturing an electrostatic chuck according to the present invention will be described briefly with reference to FIG. 2.

First, the electrode part is inserted into the body part 201. The electrode portion is composed of a terminal 204, an insulating member 205, and a first buffer layer 206a. The terminal 204 is connected to an external power source for applying power when the electrostatic chuck 200 is used in the future. The insulating member 205 surrounds the terminal 204 so as to insulate between the body portion 201 and the terminal 204. The first buffer layer 206a is formed in a predetermined region on the insulating member 205 to suppress crack generation due to thermal stress in the electrostatic chuck 200.

The electrode part is manufactured by manufacturing the terminal 204 and the insulating member 205, respectively, and then inserting and fixing the terminal 204 to the insulating member 205 and then fixing the first buffer layer 206a in a predetermined region on the insulating member 205. Form to complete. In this case, it is preferable to form the first buffer layer 206a after the insulation member 205 is shaved by cutting the insulating member 205 in the region where the first buffer layer 206a is formed on the insulating member 205. Do. In addition, the edges of the terminal 204 and the insulating member 205 are preferably processed to have a round shape. In addition, in order to lower the surface roughness, after forming the first buffer layer 206a, it is preferable to polish the surface.

Next, the second buffer layer 206b is formed. The second buffer layer 206b is formed in some regions on the body portion 201 and some regions on the first buffer layer 206a so as to suppress crack propagation due to thermal stress in the electrostatic chuck 200. In addition, it is preferable to polish the surface of the second buffer layer 206b in order to lower the surface roughness.

Finally, the base 202 in which the electrode layer 203 is embedded is laminated on the body 201 and the second buffer layer 206b to finally complete the electrostatic chuck 200. The base 202 in which the electrode layer 203 is embedded is formed by sequentially stacking the lower base layer 202a, the electrode layer 203, and the upper base layer 202b.

At this time, in order to lower the surface roughness of the lower base layer 202a, the electrode layer 203 and the upper base layer 202b (that is, to increase the surface flatness of each layer), the surface of each layer is polished after being formed. It is preferable.

On the other hand, when the lower base layer 202a is formed on the body portion 201 and the second buffer layer 206b, the upper surface of the terminal 204 protruding through the body portion 201 is formed on the lower base layer 202a. It is necessary to mask the upper surface of the terminal 204 before forming the lower base layer 202a so as not to be covered. However, the present invention is not necessarily limited to the above masking method, and after forming the lower base layer 202a on the body portion 201, a method of removing the lower base layer 202a of the corresponding portion so that the upper surface of the terminal 204 is exposed may be used. It may be.

In the above-described manufacturing method of the electrostatic chuck, the material and the forming method of each component constituting the electrostatic chuck are the same as described above.

In the present invention as described above has been described by the specific embodiments, such as specific components and limited embodiments and drawings, but this is provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments. For those skilled in the art, various modifications and variations are possible from these descriptions. Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the claims described below, belong to the scope of the present invention. something to do.

Claims

A body part having a through hole;

A base part disposed on the body part and fixing an object by an electrostatic force of the electrode, including an insertion hole corresponding to the through hole and an electrode partially exposed through the insertion hole;

A terminal portion including a connection terminal connected to the electrode through the through hole and the insertion hole, and an insulating member electrically insulating the connection terminal from the body portion;

A first buffer layer disposed on at least a part of an interface between the body part and the insulating member to block transfer of thermal stress to the insulating member; And

And a second buffer layer disposed at at least a part of an interface between the body portion and the base portion to block thermal stress from being transferred to the insulating member.
The electrostatic chuck of claim 1, wherein the first buffer layer is further disposed on an interface between the base and the insulating member.
The electrostatic chuck of claim 1, wherein the first buffer layer and the second buffer layer comprise a ceramic material.
The electrostatic chuck of claim 1, wherein the first buffer layer and the second buffer layer have a thickness in a range of 100 μm to 250 μm.
The electrostatic chuck of claim 1, wherein the surface roughness of the first buffer layer is in the range of 0.1 μm to 2 μm and the surface roughness of the second buffer layer is in the range of 3 μm to 7 μm.
The electrostatic chuck of claim 3, wherein a porosity of the first buffer layer and the second buffer layer is equal to or greater than a porosity of the ceramic base portion.
The electrostatic chuck of claim 6, wherein the porosity of the first buffer layer and the second buffer layer is 2 to 10%.
Preparing a body part having a through hole;

Preparing a terminal part corresponding to the through hole and having a first buffer layer on an outer surface thereof to absorb thermal stress of the body part;

Inserting the terminal portion into the through hole to expose the upper surface of the body portion;

Forming a second buffer layer on an upper surface of at least a portion of the body portion and an upper surface of at least a portion of the first buffer layer;

Forming a lower base layer on the body portion and the second buffer layer to expose an upper surface of the terminal portion;

Forming an electrode layer on the lower base layer in contact with an upper surface of the terminal part; And

And forming an upper base layer on the lower base layer and the electrode layer.
The method of claim 8, wherein the first and second buffer layers are coated in an atmospheric plasma spraying process.